This invention relates to an improved cutting tool for use in cutting and blanking sheet material such as corrugated board. Cutting tools of the type with which the invention is concerned may have a generally straight cutting edge intended to be translated into cutting engagement with the sheet material supported on a flat base or platen or they may have a circular edge which is rolled into cutting engagement across the sheet material on the base or platen. In either case it is an object in the design of such cutting tools that they be sufficiently sharp and sleek to cut cleanly through the sheet material but at the same time be sturdy and thick enough to withstand repeated use without undue breakage or dulling of the cutting edge.
It is recognized in U.S. Pat. No. 3,277,764 to Henc that advantages are to be gained by forming the cutting edge of the tool so that arced portions or buttresses alternate with indentures or grooves across each face of the blade, with buttresses on one side aligned with the grooves on the other side. Such a cutting edge is scalloped in elevation and undulating as viewed on edge. A principal disadvantage of that particular design, however, is that the grooves or indentures are formed with an abrupt flat end remote from the cutting edge. As the tool cuts into sheet material and the buttresses and grooves force apart the severed edges of the material, the flat ends of the grooves come bluntly into contact with the severed edges and produce a crushing effect. It is a principal purpose of the present invention to improve upon the form of such grooves so that the severed edges are cleanly separated and little or no crushing of the sheet material takes place.